Mechanical reef

ABSTRACT

A mechanical reef structure characterized by stepwise arranged deflector panels having a configuration which is effective to cause the vertically moving water in waves to absorb its own energy so that the waves are attenuated and the sand and other particulate matter carried by the water is deposited below and in front of the reef.

United States Patent 1 1 Karnas 1 1 Nov. 5, 1974 1 MECHANICAL REEF 22 Filed: July 25,1973

21 App1.No.:382,304

[51] Int. Cl E02b 3/04 [58] Field of Search 61/1 R, 5, 3, 4, 6, 49

[56] References Cited UNITED STATES PATENTS 1,175,962 3/1916 Latham 61/4 2,584,867 2/1952 Guarin l 61/5 3,415,061 12/1968 Staempfli 61/4 3,538,710 11/1970 Tourmen 1. 61/4 FOREIGN PATENTS OR APPLICATIONS 1,373,090 8/1964 France 61/5 US. Cl. 61/4 Primary ExaminerRobert R. Mackey Assistant ExaminerAlexander Grosz Attorney, Agent, or FirmWatts, Hoffmann, Fisher & Heinke C0.

[57] ABSTRACT A mechanical reef structure characterized by stepwise arranged deflector panels having a configuration which is effective to cause the vertically moving water in waves to absorb its own energy so that the waves are attenuated and the sand and other particulate matter carried by the water is deposited below and in front of the reef.

11 Claims, 6 Drawing Figures mamznm 5 m4 SHEEF 30F 3 MECHANICAL REEF SUMMARY OF THE INVENTION This invention relates generally'to method and apparatus for attenuating waves in water, and more specifically to a mechanical reef.

An object of the present invention is to provide a structure which is effective to guard against the damaging effects of waves, especially shoreline erosion, while simultaneously causing a build-up of sand or other particulate matter on the bottom below water level.

A more specific object of the present invention is to provide a mechanical reef which causes the vertically moving water in waves to absorb its own energy, whereby the waves are attenuated and the particulate matter carried by the water is deposited below and in front of the reef.

A further object of the present invention is to provide a mechanical reef having any of the characteristics described above which is of a light weight construction capable of being relatively easily positioned below the water level in any desired location.

Another object of the present invention is to provide a mechanical reef having any of the characteristics described above which can be positionedin water of substantial depth and subsequently increased in heightas the sand and otherparticulate matter gradually builds up on the bottom below water level.

Still another object of the presentinvention is to pro vide a mechanical reef having any of the characteristics described abovewhich of a relatively inexpensive construction.

The mechanical reef according to the present invention comprises a plurality of deflectors arranged in stepwise fashion extending up from the bottom below water level. The deflectors have an upwardly concave configuration such that the vertically moving water making up waves is deflected back on itself so as to dissipate the energy of the waves by turbulence. As the energy of the water is absorbed and dissipated, the transport velocity is decreased and the particulate matter carried by the water is caused to be deposited below and in front of the reef. In a preferred form of the invention, each deflector is formed on a hyperbolic spiral.

By reason of the fact that wave motion is attenuated by causing the water to absorb its own energy rather than by impact against a solid structure, the mechanical reef according to the invention can be of a light weight, relatively simple construction. This construction facilitates placement of the reef at offshorelocations. The design of the new reef is such that it can be assembled on shore and transported to the desired site of installation by suitable marine handling equipment.

The mechanical reef according to the invention is adapted for use in water of substantial depth, for example, at depths up to 100 feet and more. As the amount of sand and particulate matter deposited below and in front of the reef increases, new sections of reef can be added periodically to previously installed sections in order to increase the height of the reef. When used in this manner, the mechanical reef according to the invention makes it possible to create an accumulation of solid material in water of substantial depth and to build-up the accumulation to water level.

The mechanical reef according to the invention can be installed parallel to the area to be protected, for example, the shoreline, and can be used to effect a gradual widening of the shoreline. In the case of being installed along a shoreline, it is desirable to extend the ends of the reef into the shore at the termination points in order to preclude wave movement behind the reef. The new reef is also adapted to be installed in circular or other patterns which will be effective to protect a selected area, for example, offshore drilling equipment, etc., from wave assault.

Other objects, advantages and a fuller understanding of the invention will be had from the following detailed description and the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side elevational view of a section of reef according to the invention installed in shallow water;

FIG. 2 is an enlarged, fragmentary view of the reef shown in FIG. 1;

FIG. 3 is a fragmentary top plan view taken on the line 3-3 of FIG. 2;

FIG. 4 is a side elevational view of vertically connected sections of reef according to the invention installed in deeper water;

FIG. 5 is an enlarged elevational view of an anchoring member used in the installation of FIG. 4; and

FIG. 6 is an enlarged end elevational view of the anchoring member shown in FIG. 5.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to the drawings, FIG. 1 shows one section 10 of a mechanical reef constructed according to the present invention and installed in relatively shallow water on the bottom 11. The reef section 10 is generally comprised of a plurality of connected deflector panels 12 which are supported by a framework made up of a plurality of connected, laterally spaced, triangular frames 13 (only one of which is shown in FIG. 1). An exemplary reef section 10 may include three triangular frames 13 which are spaced apart on 8 foot centers. In a typical installation, several reef sections will be connected together end-to-end.

Each of the triangular frames l3-is formed by elongated beams, such as l-beams or channel beams, which are secured together in any suitable manner, as by bonding, bolting, riveting, etc. The elongated beams may be made of steel, although an advantage of the invention is that the beams may be made of lighter weight material such as fiberglass reinforced resin and the like. Such lighter weight materials facilitate installation of the reef section 10.

The triangular frame 13 illustrated in FIG. 1 is formed by a base member 18 and two side pieces 19, 20 which are secured to the base member 18 near its ends and extend upwardly to an apex above the base member. When the reef section 10 is used in water up to approximately 100 feet in depth, the included angle between the base member 18 and the side piece 20 which supports the deflector panels 12 may be 45. When used in depths over 100 feet, the included angle is preferably in the range of from 60 to A vertical brace 21 extends from near the center of the base member 18 to the upper ends of the side pieces 19, 20. The illustrated triangular frame 13 is additionally reinforced by a brace 22 which extends from the lower end .of the side piece 19 to the center part of the side piece 20 and by another brace 23 which extends from the connection between members 18, 21 to the connection between the members 20, 22.

The deflector panels 12 are supported along the side piece 20 in stepwise fashion by angle pieces 24. As shown in FIG. 1, each angle piece 24 is connected to the side piece 20 so that one leg of the angle piece is generally horizontal and the other leg is generally vertical. The several laterally spaced triangular frames 13 of a reef section are connected together by stringers 27. In the illustrated construction of the invention, the stringers 27 extend between and are secured to the noses of the angle pieces 24. The triangular frames 13 are additionally connected by at least one member 28 extending between and secured to the base members 18.

The upper ends of at least some of the vertical frame members 21 may have holes or eyes 30 to be used for lifting and transporting the reef section 10. If desired, a catwalk 31, shown in broken lines in FIG. 1, may be provided along the top of the framework formed by the frames 13 and it may be supported in part by extending the side pieces 20 beyond the side pieces 19.

Adjustable legs 32 are provided at the end of the base members 18 for supporting the reef section 10. Each leg construction comprises a pointed head 33 which is embedded in the lake or sea bottom 11. As shown, the head 33 is generally in the shape of a four-bladed arrow broadhead, but it is to be understood that the exact configuration may vary depending upon the particular substance of the bottom 11, for example, mud, shale, sand, etc. A shaft 34 extends up from the base of the head 33 through a sleeve 35 secured on an end of a base member 18. The shaft 34 is adjustable vertically through the sleeve 35 so that the reef section 10 can be positioned with the base members 18 nearly horizontal.

The deflector panels 12 may be made of a steel, glass fiber reinforced resin or the like. Each deflector panel has an arcuate configuration and presents an upwardly concave surface. In the preferred construction of the invention, each deflector panel 12 is formed on an hyperbolic spiral and includes as an integral structure an upwardly curved forward lip section 40, a curved rear section 41, a back section 42 projecting up from the rear section 4], and a reversely curved top section 43. The sections 40, 41 cooperate to form an upwardly opening channel 44.

The reversely curved top section 43 of each lower panel engages the outside surface of the lip section of the adjacent upper panel and is connected to it by fasteners 47. The back panel sections 43 are secured to the vertical legs of the angle pieces 24 by similar fasteners so that the bottoms of the channels 44 rest on the horizontal legs of the angle pieces.

The deflector panels 12 have sand ports 45 in the channels 44. As is best shown in FIG. 3, the sand ports 45 are defined by cowls 46 which are located in the bottoms of the channels 44 and open toward the rear panel sections 42. The lips of the cowls 46 which define the ports 45 are preferably at an angle of about 45. This preferred construction in which the ports 45 are at a 45 angle minimizes clogging by contributing to a vortex water action in the channels 44 which washes the debris away from the ports. The ports 45 may be formed about two feet apart along the width of the panels.

Although the deflector panels 12 may vary widely in size, an exemplary panel contemplated by the invention may be on the order of about 10 feet high and about 20 feet wide. The ratio of the height of the panel to the width of the channel 44 at its mouth may be on the order of 2: I. When a plurality reef units 10 are installed side-by side, the side edges of adjacent panels 12 are overlapped and connected together by fasteners 47 as shown in FIG. 3.

It is well known that the water which makes up a wave does not travel laterally with it. Instead, each particle of water moves locally in a circular or elliptical orbit lying in a vertical plane. Thus, the water in waves may be considered as moving vertically so that as a series of waves travel past a fixed location, the water at that location moves upward in the zones of the wave crests and downward in the zones of the wave troughs. It is also known that, depending on the surface wind velocity and other factors, the vertical water movement can take place at great depths of several hundred feet.

Referring to FIG. 1, the vertical water movement of waves at the location of the reef section 10 is diagrammatically represented by arrows 50, 51. When constructed according to the present invention, the panels 12 are effective to intercept the downwardly moving water 51 in the vertical zones of the wave troughs. The downwardly moving water whirls or spins in the channels 44 to produce a condition of turbulence in and above the channels 44. This results in the kinetic energy of the waves being dissipated primarily by collision of the water particles rather than by impact on the reef 10. As the energy of the waves is dissipated, the volume of sand and other particulate matter which the water can transport becomes less and the particulate matter is deposited in the channels 44 during upward movement of the water in the zones of the wave crests. When the water subsequently moves down during the next wave trough, the sand previously deposited in the channels 44 is washed through the ports 45 by the spinning action of the water. This action continues so that the sand and other particulate matter gradually builds up below and in front of the reef 10. The particulate matter which accumulates below the reef 10 more firmly anchors the reef in position and acts as a natural barrier to protect the shoreline or other area guarded by the reef.

The purpose of the preferred hyperbolic spiral configuration of the panels 12 is to neutralize or reduce the velocity of the largest volume of water possible in order to settle out the maximum amount of particulate matter and also to neutralize the lateral forces on the panels so that the reef is not required to be constructed of heavy steel members. Referring to FIG. 2, the water which moves down adjacent the reversely curved top section 43 and the back section 42 of each panel 13 creates a negative pressure in the general area delineated by the broken line 55. The reversely curved sections 43 are thus effective to minimize laterally deflecting forces on the backs of the panels 12. Within the channels 44, the directional force on the panel lip section 40 is indicated by the arrow 56 and the directional force on the rear section 41 is indicated by the arrow 57. The forces 56, 57 tend to neutralize each other with the resultant force indicated by the arrow 58 being substantially vertical, whereby the force of the water tends to stabilize the reef in its intended upright position.

FIG. 4 shows an assembly 65 of several-reef sections .10 vertically connected together to provide a continuation of the stepwise arrangement of the panels 12. The assembly 65 is obtained by connecting the forward ends of the base members 18' of each reef section 10 to the upper ends of the vertical braces 21 of the next lower reef section. Braces 66 which parallel the side pieces 20 are connected between the rear ends of the brace members 18. Sand anchors 67, 68 are connected to the four superposed reef sections 10 at the rear ends of the base members l8'in order tosupport the assembly 65.

The sand anchors 67, 68 are identical in construction except for size and are more particularly shown in FIGS. 5 and 6 as comprising a vertical rod 75 which is vertically adjustable through a sleeve 76 secured to the end of the member 18. The rod 75 carries at its lower end a four-bladed, pointed head 77. As. in the caseof the similarly shaped head 33-of each leg32, the head configuration may vary dependingupon the substance of the lake or sea bottom in which the head is embedded. Tie rods 78 extend from the sleeve 76 to the head 77 and a tie rod spreader plate 79 is provided in a vertically adjustable positiononthe rod 75.

Referring particularly to FIG. 6, it will be seen that the rod 75 is tubular and that it is internally reinforced by angle iron inserts 80. Compressed air connections 81 are provided at the top of the tubular rod 76 and compressed air outlet ports 82 areprovided in the head 77 along the bases of the blades. In use, compressed air is admitted to the rods 75 of the sand anchors in order to facilitate embedding of the heads 77.

As contemplated by this invention, a reef section 10 or a plurality of reef sections laterally connectedto form a first tier level are positioned on the bottom below water level. When the sand or other particulate matter builds up to a level approximately indicated by reference numeral 85 in FIG. 4, a second tier of reef sections is connected to the previous installation. This second tier is supported by sand anchors 67 which are embedded in the water bottom. The particulate matter is then allowed to accumulate to a level generally indicated by reference numeral 86 whereupon a third'tier of reef sections supported by sand anchors 68 is installed. Any number of additional tiers are installed in a similar way in order to build the accumulation of particulate matter to the desired height above the original water bottom.

It will be seen from the above that the invention achieves the objectives of providing a simply constructed, easily installed mechanical reef which effectively prevents erosion while causing a build-up of sand and other particulate matter. The preferred construction is such that these objectives are obtained by causing the waves to absorb or attenuate their own energy, whereby the new reef may be constructed of relatively light weight materials and easily maintained in position. It will also be seen that the invention achieves the obof the foregoing detailed disclosure. Therefore, it is to be understood that, within the scope of the appended claims, the invention can be practiced otherwise than is specifically shown'and described.

What is claimed is: i

L A mechanical reef for attenuating waves in water comprising a plurality of deflector panels, each of said panels having an arcuate configuration and presenting an upwardly concave surface which defines a channel, and frame means supporting said panels in a stepwise arrangement so that the channels defined by said panels are positioned to intercept the downwardly moving water in waves, whereby the downwardly moving water enters the channels and whirls in a turbulent manner to dissipate its kinetic energy.

2. A mechanical reef as claimed in claim 1 wherein said panels include sand ports in the bottoms of said channels.

3. A mechanical reef for attenuating waves in water comprising a plurality of deflector panels, each of said panels including a forwardly and upwardly curved lip section, a rearwardly and upwardly curved rear section which cooperates with said lip section to define an upwardly opening channel extending laterally of the panel, at least one sand port in the bottom of said channel, and a back section projecting up from said rear section; and frame means supporting said panels in a stepwise arrangement so that the channels formed by said panels are positioned to intercept the downwardlymoving water in waves, whereby the downwardly moving water enters the channels and whirls in a turbulent manner to dissipate its kinetic energy.

4. A mechanical reef as claimed in claim 3 in which said sand port opens toward said rear panel section.

5. A mechanical reef as claimed in claim 3 in which the ratio of the height of each panel to the width of said channel is about 2:1.

6. A mechanical reef as claimed in claim 3 in which each of said panel sections has the shape of a segment of a hyperbolic spiral.

7. A mechanical reef as claimed in claim 6 in which each of said panels further includes a top section which extends from said back section and is reversely curved jective of providing av reef which can be gradually inwith respect to said back section.

8. A mechanical reef assembly for attenuating waves in water comprising:

a. a plurality of similarly constructed sections; b. each of said reef sections including:

i. frame means,

ii. deflector panels supported by said frame means in stepwise fashion,

iii. each of said panels having an upwardly concave surface which defines an upwardly opening channel extending laterally of the panel, and at least one sand port in the bottom of said channel, and

c. said reef sections being connected together on top of one another to provide a continuous stepwise arrangement of said panels so that the channels defined by said panels are positioned to intercept the downwardly moving water in waves, whereby the downwardly moving water enters the channels and whirls in a turbulent manner to dissipate its kinetic energy.

9. A reef assembly as claimed in claim 8 in which said panels have a shape corresponding to a segment of a hyperbolic spiral.

LII

the vertical zones of wave troughs and deflecting the water in an upward direction by means including a series of elongated, upwardly opening channels arranged in stepwise fashion, each of said channels being defined by a curved lip section and a curved rear section, whereby the water in the channels impinges upon itself to dissipate the wave energy by turbulence. 

1. A mechanical reef for attenuating waves in water comprising a plurality of deflector panels, each of said panels having an arcuate configuration and presenting an upwardly concave surface which defines a channel, and frame means supporting said panels in a stepwise arrangement so that the channels defined by said panels are positioned to intercept the downwardly moving water in waves, whereby the downwardly moving water enters the channels and whirls in a turbulent manner to dissipate its kinetic energy.
 2. A mechanical reef as claimed in claim 1 wherein said panels include sand ports in the bottoms of said channels.
 3. A mechanical reef for attenuating waves in water comprising a plurality of deflector panels, each of said panels including a forwardly and upwardly curved lip section, a rearwardly and upwardly curved rear section which cooperates with said lip section to define an upwardly opening channel extending laterally of the panel, at least one sand port in the bottom of said channel, and a back section projecting up from said rear section; and frame means supporting said panels in a stepwise arrangement so that the channels formed by said panels are positioned to intercept the downwardly moving water in waves, whereby the downwardly moving water enters the channels and whirls in a turbulent manner to dissipate its kinetic energy.
 4. A mechanical reef as claimed in claim 3 in which said sand port opens toward said rear panel section.
 5. A mechanical reef as claimed in claim 3 in which the ratio of the height of each panel to the width of said channel is about 2:
 6. A mechanical reef as claimed in claim 3 in which each of said panel sections has the shape of a segment of a hyperbolic spiral.
 7. A mechanical reef as claimed in claim 6 in which each of said panels further includes a top section which extends from said back section and is reversely curved with respect to said back section.
 8. A mechanical reef assembly for attenuating waves in water comprising: a. a pluralIty of similarly constructed sections; b. each of said reef sections including: i. frame means, ii. deflector panels supported by said frame means in stepwise fashion, iii. each of said panels having an upwardly concave surface which defines an upwardly opening channel extending laterally of the panel, and at least one sand port in the bottom of said channel, and c. said reef sections being connected together on top of one another to provide a continuous stepwise arrangement of said panels so that the channels defined by said panels are positioned to intercept the downwardly moving water in waves, whereby the downwardly moving water enters the channels and whirls in a turbulent manner to dissipate its kinetic energy.
 9. A reef assembly as claimed in claim 8 in which said panels have a shape corresponding to a segment of a hyperbolic spiral.
 10. A reef assembly as claimed in claim 8 wherein each of said panels is formed as an integral structure including a curved lip section, a curved rear section cooperating with said lip section to form said channel, and an upper portion extending from said rear section, said upper portions of lower panels being connected to the lip sections of overlying panels.
 11. A method of attenuating waves comprising the steps of intercepting the downwardly moving water in the vertical zones of wave troughs and deflecting the water in an upward direction by means including a series of elongated, upwardly opening channels arranged in stepwise fashion, each of said channels being defined by a curved lip section and a curved rear section, whereby the water in the channels impinges upon itself to dissipate the wave energy by turbulence. 